This application is a division of application Ser. No. 09/901,016 filed Jul. 10, 2001 now U.S. Pat. No. 6,652,807, which claims the benefit of U.S. Provisional Application No. 60/218,048 filed Jul. 13, 2000.
This invention relates to apparatus for collecting and concentrating analytes within a liquid medium for the purpose of identifying and quantifying the analytes using Raman, surface enhanced Raman scattering (SERS), infra-red (IR) or fluorescence measurement techniques.
Ciguatoxin is the major causative toxin in ciguatera fish poisoning, a disease which remains a serious fisheries and public health problem worldwide wherever reef fish are caught and consumed. Annual worldwide estimates of people afflicted by ciguatera poisoning range from 500,000 to 1,000,000. In the United States, ciguatera is the single, leading cause of seafood poisoning. Worldwide, only 10 percent of all ciguatera cases are probably reported (Lewis, 1986). During the past five years, increased reports of ciguatera have also been documented in Mexico (Lechuga-Deveze and Sierra-Beltran, 1995; Arcila-Herrera et al., 1998; Sierra-Beltran et al., 1998), California (Barton et al., 1995), and temperate countries such as Canada (Bruneau et al., 1997; De Haro et al., 1997; Kelmme and Losch, 1997; Sanner et al., 1997; Blume et al., 1999), that import fish from ciguateric regions or whose residents travel to endemic ciguatera areas and contract the disease.
Although the ciguatera toxin-producing organism may not be considered a traditional pathogen, it does have significant global impact on human health, fisheries and their dependent economies. Ciguatera often manifests itself similar to a severe flu, causing weakness, diarrhea, muscle pain, joint aches, nausea, chills, headache, sweating and dizziness. These symptoms are often accompanied by numbness or tingling around the mouth and in the extremities, and a strange sense of temperature reversal where hot items feel cold to the touch and cold objects feel hot. Symptoms typically persist for days or weeks, but may last for months or years. Deaths are rare but can occur in severe or complicated cases.
The occurrence of ciguatera toxins in many fishes can prevent many commercially important fishes from being utilized in states or island nations with limited resources. Consequently, ciguatera can have devastating impacts on the development of small-scale commercial fisheries. In 1984, the economic losses in Florida, the Caribbean and Hawaii due to ciguatera totaled over $10 million annually. Given the rise of inflation and the continued existence of ciguatera, this figure today represents a significant loss in revenue for the fishing industries in these areas as well as those in other ciguatera affected countries. Thus, the areas that need a test method to rapidly screen fish for ciguatoxin include ciguatera endemic areas such as Hawaii, Florida, Guam, the Philippines, Japan, and the Caribbean; commercial fisheries in these areas as well as countries importing seafood from these areas; and diagnostic laboratories.
The major marine toxins associated with ciguatera poisoning have been attributed to the class of chemicals designated ciguatoxin (CTX) and its congeners. Currently, Oceanit Test Systems (OTS), a subsidiary of Oceanit Laboratories, Inc. (Oceanit), offers the only commercially available CTX detection kit, CIGUA-CHECK®, developed by Oceanit and marketed since October 1997. Although past research has proven that CTX screening using the monoclonal antibody used in the CIGUA-CHECK® system is effective in preventing ciguatera and can provide results within one hour, this method is designed primarily for small-scale home or field use. In order to screen potentially toxic fish from ciguatera-endemic areas, however, an even simpler, larger scale technique needs to be designed to prevent consumption of seafood tainted with CTX as well as to aid in confirming ciguatera cases caused by this toxin in the United States as well as other affected nations.
Measuring trace amounts (in parts per trillion or less) of analytes usually requires specialized techniques. Recent advances in Raman, IR and fluorescence spectroscopy have enabled increased sensitivity to detect such analytes. While methods based on identifying analytes based on their unique chemical and physical properties exist, most require considerable sample preparation and the use of expensive detectors. The need exists for techniques to measure trace amounts of analytes simply and rapidly. One example of such a trace analyte is CTX.
There is a need to prevent human illness due to ciguatera toxins by creating an innovative method to detect these harmful toxins in fish before they are incidentally ingested.